1. Field of the Invention
This invention has relation to sign assemblies of the type in which a flexible sign panel is removably installed in a rectangular sign frame, held securely in that sign frame, and can then be easily removed from it without the aid of additional tools or equipment all from the front face of the sign frame.
2. Description of the Prior Art
Sign assemblies are known in which a flexible sign panel is installed from the front of a sign frame in such a manner that the end edges of the panel fit within undercut lips of the sign frame to firmly position the panel against removal or tampering; but where inward bowing of the sign panel exposes a hidden recess in the frame into which a tool can be inserted to pry the panel loose from the sign frame. Such a structure is disclosed in my U.S. Pat. No. 4,268,984 granted to Taylor in May of 1981.
Another patent which discloses structure whereby an end portion of a flexible sign panel can be made to extend away from its sign frame by depressing another portion of that panel is U.S. Pat. No. 2,043,760 granted to Marsh, granted in June of 1936.
In U.S. Pat. No. 513,714 granted to McArdle et al. in January of 1894, sheet metal sign frames are disclosed in which a raised stiffener or corrugation B extends across the center of the sign frame. In addition to stiffening the sheet metal frame, this corrugation B can also serve to firmly hold the sign panel or card firmly against the strips G to help to constantly maintain the card under tension.
U.S. Pat. No. 2,362,273 granted to Hopp in November of 1944 discloses a flexible sign panel supported under overhanging lips at opposite ends of the panel with a pair of longitudinally extending protrusions each adjacent to and parallel to one of the overhanging lips so that the sign panel is maintained in tension when so mounted. The sign panel is maintained in a bowed shape so that it can be easily removed simply by grasping opposite edges of it and withdrawing it, or by sliding it longitudinally out the end of the sign frame. A protective device consisting of a transparent body member 30 including a rigid main body portion 32 is fastened in place by screws so that the sign cannot be tampered with.
Located in a search of the prior art are the following patents which, while some of them have structures which may appear superficially similar to portions of the present invention, it is believed that they do not relate to the inventive concept of the present invention:
U.S. Pat. Nos. 2,851,804 granted to Roach in September of 1958; 2,181,976 granted to Lotz in December of 1939; 2,180,195 granted to Cavalero in November of 1939; 2,172,528 granted to Auer in September of 1939; 2,817,914 granted to Rosen in December of 1957; 1,787,308 granted to Furlong in December of 1930; 1,053,724 granted to Gardner et al. in February of 1913;and 641,287 granted to Goodwin in January of 1900.
What did not exist before the present invention was a front loading sign frame assembly in which a flexible sign panel could be installed in a multi-sided sign frame to lie perfectly flat in that frame and to appear to be completely inaccessible and unremovable; but which can be easily removed, substituted for, and/or reinstalled by the initiated over and over without the use of tools or apparatus other than the sign assembly itself.